Guide to build a modern Web App using Next.js 14 (App Router), NextAuth, Theming, Tailwind CSS, and i18n

Next.js has gained significant attention in web development due to its simplicity, power, and flexibility, making it a favorite choice for developers. It offers a framework with routing, server-side rendering, static site generation, and API routes. Next.js is impressive due to its server-side rendering, static site generation, hybrid model, and API routes. The App Router in Next.js 13 offers advanced features like layouts, loading UI, and colocation of data and UI, making it more efficient, maintainable, and scalable. NextAuth.js provides a straightforward way to apply powerful authentication in web apps, featuring secure defaults, OAuth providers, and serverless compatibility. Tailwind CSS is a popular utility-first CSS framework that allows developers to create responsive, scalable interfaces without custom CSS, making it suitable for Next.js apps. It is highly customizable and supports responsive design. Next.js can handle theming easily using "next-themes" combined with Tailwind CSS. Global applications can support multiple languages using Next.js with "i18next" for internationalization. A practical example of a website developed using Next.js 14 with App Router, full authentication, responsive web design, i18n, and multiple themes support is available on GitHub.